During the second year of this investigation we shall complete studies in normal and asthmatic children which are already in progress. The goal of these studies is to define differences in cardiorespiratory adaptations to strenuous exercise between normal and asthmatic children, and how various drugs (atropine, aspirin, phentolamine) affect pathological adaptations of asthmatic children who develop exercise-induced bronchospasm (EIB). It will also be determined at what level of exercise asthmatic children develop EIB and whether this level corrosponds to their anaerobic threshold, i.e. the level at which metabolic acidosis begins to develop.